With the advent of electric and hybrid electric vehicles, vehicle operators are looking for convenient ways to charge their vehicles, and in particular, more places to charge their vehicles. This has led to the development of portable charge-cord sets that make it possible for the vehicle to be charged at various locations, but as a result, the vehicle operator may be using an electrical outlet of unknown quality. Because an electric vehicle may draw a relatively large amount of current—e.g., 13 amps (A) from a standard 120 volt (V) outlet—when it is charging, a poor quality outlet or circuit to which the outlet is connected, could lead to the outlet overheating.
In the case where an electrical outlet is overheating during a vehicle charging, the plug on the end of the charge-cord may or may not also reach an unacceptably high temperature. Even if some of the heat transfers from the outlet to the plug, the heat transfer will largely be conductive, and inefficient. Therefore, measuring the temperature of the cord, or even the plug on the end of the cord, will likely not provide a good indicator of the temperature of the outlet. Further complicating the issue is that a vehicle may be charged in a relatively cold ambient environment, such as in a garage. In such cases, the plug on the end of the charge-cord, may remain very cool throughout the charging process, while the electrical outlet becomes unacceptably hot. Therefore, a need exists for a thermal protection system for an electrical device, such as an electrical outlet, but which resides within the device over which the vehicle operator has control—e.g., a charge-cord set.